Parts, such as graphite shields and electrodes, need to be fastened to other components within an ion implanter or other plasma processing tool. Previous methods of fastening have used stainless steel vented shoulder screws or bearing shims. However, stainless steel or other metal fastening devices have two drawbacks. First, when over-tightened, these devices may crack the part being fastened to another component. Second, stainless steel or other metals contaminate the beam or workpiece being processed or implanted. Merely covering a stainless steel or other metal fastener with a supplementary graphite shield increases material costs and complexity without addressing the problem of over-tightening parts. Graphite itself is also prone to cracking. If a supplementary shield or graphite fastening device cracks, it may prevent or impede repair or replacement.
Accordingly, there is a need in the art for an improved fastening apparatus and, more particularly, a fastening apparatus that prevents over-tightening and that reduces contamination from stainless steel or other metals.